History lessons for little readers

A photograph serves as the frontispiece for James M. McPherson's Fields of Fury: The American Civil War. A farm boy in overalls and straw hat holds up two handfuls of what appear to be pebbles. In reality, they're bullets, some from the guns of Confederate soldiers, some from Union weapons. The viewer can't tell which is which, and therein lies a lesson breathtaking in its simplicity....